How do I get straight brows? Brow lowering? (Photo)

While the brow can be lowered, your problem is more of a muscular imbalance. Muscles lower the brow (corrugated, procerus, depressor), and muscles raise the brow (frontalis).  The basics for this were worked out in 1852 by Duchenne.  There is an "agonist/antagonist" relationship with these muscles.  In your case the dominance of the muscles that "scrunch" the medial brows down are responsible for your brow position not being straight and the "angry" look that you have.  
One brow is also higher than the other.  That may be a natural imbalance, or you may be a "unilateral brow lifter".  This needs to be taken into consideration.  
It is essential to evaluate you "in motion".  It is probable that an endoscopic approach will work for you. The brow can be "shaped". You can simulate this with Botox injections into the proper muscles.  The Botox may not give the exact results, but you might get an idea of the changes.

Hello,While you may consider lowering your brow, I think you would be best served by having a brow lift. This can be done endoscopically or via a direct incision at your brow hair line. If you look at the web link provided, go to case # 2302. While he had many other things performed, his brow position was an issue for him. Raising his brows helped with the heavy look of his eye region. His eyebrows were still horizontal after surgery. Hope this helps.Sincerely, Dr. K